The purpose of this research project is to screen, and comprehensively test monoclonal antibodies (Mabs) by immunohistochemistry, in order to identify those capable of increasing the accuracy of histological diagnosis of, alternatively, those which recognize marker substances of prognostic significance. Mabs obtained from various external sources as well as produced in our own laboratory will be extensively screened against a panel of normal human tissues and selected neoplasms of variable histogenesis and degrees of differentiation. Frozen tumors from our frozen tumor bank will serve as the "golden rule" for comparative studies with paraffin embedded tissues. Freeze- dried (unfixed) tissue, ethanol-fixed and formalin-fixed tissues, all embedded in paraffin will be tested with each Mab. Various immunohistochemical methods will be initially employed on frozen and paraffin embedded tissues to maximize selection of the optimal handling for each antigen/antibody. Antibodies which after rigorous screening show tissue or tumor discriminatory capacity will be tested against a larger group of well characterized neoplasms of appropriate type depending on the specificity shown during screening. To facilitate screening in search of markers of biological significance, especially prepared multi-tumor blocks containing samples of neoplasms from clinically-defined patient populations will be used. The results of the immunohistochemical studies will be correlated with the histopathologic diagnosis, tumor grade, stage of disease, response to therapy, survival and other prognostic parameters of specific significance for the neoplasms involved.